Final answer:
Congress was powerless to act against Shays' Rebellion due to the limitations of the Articles of Confederation, necessitating privately funded local militias to quell the uprising, eventually leading to the Constitutional Convention.
Step-by-step explanation:
The question concerns why Congress did not act against Shays' Rebellion. The correct answer would be b) Congress was powerless to act. The Articles of Confederation provided a weak central government without the authority to raise an army to deal with such insurrections.
As the situation in Massachusetts escalated, the government realized its inability to intervene due to its limited powers. Local militias, funded through private means by concerned wealthy citizens, ultimately quelled the rebellion. The uprising highlighted the necessity of a stronger national government, leading to calls for the revising of the Articles, which eventually resulted in the drafting of the U.S. Constitution by the Constitutional Convention.